The present disclosure relates to storage management, and more specifically, to storage management of local devices in tiered systems.
A data storage system may have one or more storage tiers in one or more storage devices. Tiered storage is a data storage environment consisting of two or more kinds of storage delineated by differences in at least one of these four attributes: price, performance, capacity and function. Any significant difference in one or more of the four defining attributes may be sufficient to justify a separate storage tier.
The data storage system may include storage tiers on a client computer. For instance, the client computer may have a local storage tier that is accessed by a tiered storage controller in order to reduce access times for the client computer for data in the data storage system.
Extents may be managed on tiered storage. An extent is a contiguous area of storage in a computer file system, reserved for a file. When a process creates and writes data to a file, file-system management software allocates a whole extent. When resuming a write to the file, possibly after doing other write operations, the data continues where the previous write left off. This may reduce or eliminate file fragmentation and possibly file scattering too. An extent-based file system (i.e., one that addresses storage via extents rather than in single blocks) need not require limiting each file to a single, contiguous extent.